media: cx23885: Fix snd_card_free call on null card pointer

Currently a call to snd_card_new that fails will set card with a NULL
pointer, this causes a null pointer dereference on the error cleanup
path when card it passed to snd_card_free. Fix this by adding a new
error exit path that does not call snd_card_free and exiting via this
new path.

Addresses-Coverity: ("Explicit null dereference")

Fixes: 9e44d632 ("[media] cx23885: Add ALSA support")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>